Sunita Williams becomes 2nd-ever female commander of the Space Station

Sunita Williams is taking over the command post of the Space Station as 3 astronauts prepare to head back to earth.

Astronaut Sunita Williams of the US gestures before boarding the Soyuz TMA-05M spacecraft at the Russian-leased Baikonur cosmodrome on July 15, 2012. (VYACHESLAV OSELEDKO/AFP/Getty Images)

Sunita Williams, an accomplished NASA astronaut, will become the second-ever woman to be commander of the International Space Station, as three astronauts prepare for their journey back to earth Sunday.

Williams will replace Russian Gennady Padalka, who is returning to Earth after being the commander of the six-person Expedition 32 crew, NBC News reported.

"I would like to thank our [Expedition] 32 crew mates here who have taught us how to live and work in space, and of course to have a lot of fun up in space," Williams told Padalka during a change of command ceremony.

Russian astronaut Segei Revin and NASA's Joe Acaba are also heading home after a four-month mission at the Space Station. Their landing is scheduled for Landing is scheduled for 10:53 p.m. in a remote desert in north-central Kazakhstan, according to MSNBC.

The three returning astronauts are expected to have a difficult time readjusting to life on earth, especially Revin and Acaba, who are coming off their first long-term stay aboard the orbiting international space lab, NBC News reported.

"The goal is to get their strength and all their function back to their preflight baseline," said NASA flight medical officer Steve Gilmore of the rehabilitation programs the three will undergo. "And in 45 days, with folks working hard, typically we get people to where they were before they launched."

Williams will be sharing the Space Station with Russia cosmonaut Yuri Malenchenko and Japanese astronaut Akihiko Hoshide until mid-October, when three more astronauts will arrive and round out the full crew of Expedition 33, according to NBC.